Add native iOS notifications (#64)

TESTING.md

@@ -243,6 +243,7 @@ source update are published, and installs or updates Gotcha through AltStore PAL
       background with no border or pill and defaults to the clock. Select the
       issue and pull-request icons in turn; each shows only matching recent
       activity or the native empty state, then the clock restores all rows.
+      The bell remains a separate, accessible Notifications destination.
 - [ ] Pull-request activity includes older creation and close events beyond the
       first activity-feed page without requiring a manual pull-up; the empty
       state appears only after every available page has been checked.
@@ -251,6 +252,40 @@ source update are published, and installs or updates Gotcha through AltStore PAL
       Back button and left-edge interactive swipe return directly to Home.
 - [ ] Non-linkable server activity does not navigate or appear tappable.
 
+## Notifications
+
+- [ ] Launch a fresh install. Gotcha does not request notification permission
+      at launch. Open Settings and turn on **Background notifications**; only
+      then does the standard iOS authorization sheet appear. Deny once and
+      confirm Gotcha keeps the switch off, explains that notifications are
+      disabled, and offers **Open Settings**. The **Notification Settings** row
+      opens Gotcha's page in iOS Settings.
+- [ ] Allow notifications. Settings reports the current system authorization,
+      the app switch persists across relaunches, and iOS Settings remains the
+      source of truth for alerts, sounds, Focus, and scheduled summaries.
+      Turning the app switch off cancels pending alerts and background refresh.
+- [ ] Tap the Home bell. Open and Closed each show the matching server
+      notification threads with a type icon, title, repository, date, Dynamic
+      Type layout, and accessible Open/Closed value. Pull to refresh, switch
+      status repeatedly, and load a list longer than one page without duplicate
+      or stale rows.
+- [ ] Tap open and closed issue, pull-request, commit, and repository
+      notifications. Each opens the native destination on the Home navigation
+      stack; opening an unread thread marks it read, Back returns to the
+      notification list, and the next refresh moves it from Open to Closed.
+- [ ] After the first poll establishes a cursor, create or receive another
+      server notification and background Gotcha. From Xcode's debugger, run
+      `e -l objc -- (void)[[BGTaskScheduler sharedScheduler] _simulateLaunchForTaskWithIdentifier:@"de.rfc1437.gotcha.notifications.refresh"]`.
+      Confirm one ordinary-priority local notification is delivered with no
+      private issue title or repository name on the Lock Screen. A repeated
+      update replaces the same thread alert rather than stacking duplicates;
+      tapping it selects the correct configured server, opens the originating
+      item, and marks the Gitea thread read.
+- [ ] Bring Gotcha to the foreground while a poll finds an update. It refreshes
+      notification data without displaying a banner over the active app. Leave
+      it backgrounded and confirm iOS, not an in-app timer, chooses subsequent
+      refresh timing.
+
 ## Milestone navigation
 
 - [ ] Open a milestone, then open one of its issues and one of its pull